Varenicline (Champix®)

Varenicline is only available by prescription from your doctor. It blocks the effects of nicotine and reduces cravings and withdrawal symptoms. If you start smoking again while taking the medicine, you won't feel as satisfied. This improves your chances of quitting.


Varenicline works by changing the way the brain reacts to nicotine. It makes it harder to get pleasure from nicotine and also helps to reduce cravings by blocking the receptor in the brain that responds to nicotine. Other advantages include:

  • It doubles or triples your chances of quitting successfully
  • It's easy to use
  • It does not contain nicotine, which is important to some people

Common side effects

  • Nausea and vomiting
  • Gas and constipation
  • Insomnia and abnormal dreams
  • Headache
  • Mood & behavioural change

How to use

Varenicline is available as a pill that you take by mouth. You will need a prescription from your doctor.

  • Note: Start taking varenicline two weeks before you quit smoking. This builds up the level of medicine in your body.
  • Continue to smoke as usual while taking varenicline until your quit date.
  • The recommended dose of varenicline to help you quit smoking is:
    • Days 1-3: take one 0.5mg tablet once a day.
    • Days 4-7: take one 0.5mg tablet twice a day, once in the morning and once at night.
    • Day 8 to the end of treatment: take one 1mg tablet twice a day, once in the morning and once at night.
  • Take varenicline after eating and with a full glass of water to decrease the nausea and vomiting side effect.

Warnings & precautions


Health Canada is reviewing the stop-smoking drug Champix (varenicline tartrate) and potential risk of heart problems in patients with heart disease (June 27, 2011).

Do not use varenicline if one of the following applies to you:

  • Have an allergy to varenicline
  • Currently using nicotine replacement therapy (like gum or patch). The combination of taking both does not increase your chance of quitting and increases the likelihood of experiencing side effects.
  • Less than 18 years old
  • You are pregnant

Speak to a doctor or pharmacist about whether varenicline is right for you if one of the following applies to you:

  • Depression or other mental health problems
  • Breast-feeding
  • Kidney problems
  • Currently taking medications such as insulin, theophylline, or warfarin

Stop taking varenicline and speak to your doctor immediately if you experience any of the following symptoms:

  • Depressed mood
  • Agitation
  • Changes in behaviour that are not typical
  • Suicidal thoughts or behaviour
  • Thoughts of harming yourself or others